The continued inclusion of antimicrobial agent triclosanAntimicrobial agent triclosan (TCS) in heavily used pharmaceutical and personal care products (PPCPs)Pharmaceutical and Personal Care Products (PPCPS), especially during disease outbreaks such as the COVID-19COVID-19 pandemicPandemic in several south Asian countriesSouth asian countries, have raised concerns among healthcareHealthcare professionals, researchers and the general public. The side effects of TCS’ presence in water sources, particularly drinking waterDrinking water, have now encouraged further studies in water treatment. The research in this work encompasses a mathematical model-based prediction of TCS-water crossflow nanofiltrationNanofiltration (NF) behaviour through coupled MATLABMATLAB image processing and COMSOLCOMSOL multiphysics simulations. The NF system geometry focused on was the spiral channel at the base of the filtration cell where the free and porous flow domains were modelled through a coupling of Navier–Stokes equationsNavier-stokes equations and Darcy’s lawDarcy’s law using the Beavers-Joseph interfacial condition. The simulation demonstrated the correlationCorrelation between the TCS concentrationConcentration distribution and the dissipation of crossflow velocityVelocity on the membrane surface. Altering process parameters such as inlet pressure, inlet concentrationConcentration and porosity were also found to distinctively influence the spread of TCS on the membrane surface, while permeate flux was mainly affected by membrane permeabilityPermeability. The results of this study suggest that optimisation of these process parameters following the patterns observed through the model would be highly beneficial for the improvement and sustainableSustainable design of NF systems for TCS-water separation.